Если весь текст в презентации виден в представлении Outline, вы должны быть в состоянии сделать File | Сохранить как | Выберите Outline (RTF).
В противном случае вам понадобится немного VBA.  На моем сайте часто задаваемых вопросов по PowerPoint есть несколько примеров:
Экспорт текста в текстовый файл, извлечение текста из PowerPoint (Mac или ПК):
См .: http://www.pptfaq.com/FAQ00274_Export_Text_to_a_text_file-_extract_text_from_PowerPoint_-Mac_or_PC-.htm
  Он сохраняет текст из каждой фигуры на страницах заметок в файл с именем NotesText.TXT в той же папке, что и сама презентация PowerPoint.
Sub SaveNotesText()
Dim oPres As Presentation
Dim oSlides As Slides
Dim oSlide As Slide
Dim oShapes As Shapes
Dim oSh As Shape
Dim NotesText As String
Dim FileNum As Integer
Dim PathSep As String
#If Mac Then
    PathSep = ":"
#Else
    PathSep = "\"
#End If
Set oPres = ActivePresentation
Set oSlides = oPres.Slides
For Each oSlide In oSlides
    NotesText = NotesText & "Slide " & oSlide.SlideIndex & vbCrLf
    Set oShapes = oSlide.NotesPage.Shapes
    For Each oSh In oShapes
        If oSh.HasTextFrame Then
            If oSh.TextFrame.HasText Then
                NotesText = NotesText & oSh.TextFrame.TextRange.Text
            End If
        End If
    Next oSh
    NotesText = NotesText & vbCrLf
Next oSlide
FileNum = FreeFile
Open oPres.Path & PathSep & "NotesText.TXT" For Output As FileNum
Print #FileNum, NotesText
Close FileNum
End Sub
  Вот макрос от Криса Ландера, который будет экспортировать весь текст на каждом слайде в презентации. Немного изменил его, чтобы он работал на Mac и различал заголовок, подзаголовок, текст и другой текст.
Sub ExportText()
  Dim oPres As Presentation
  Dim oSlides As Slides
  Dim oSld As Slide         'Slide Object
  Dim oShp As Shape         'Shape Object
  Dim iFile As Integer      'File handle for output
  iFile = FreeFile          'Get a free file number
  Dim PathSep As String
  Dim FileNum As Integer
  #If Mac Then
    PathSep = ":"
  #Else
    PathSep = "\"
  #End If
  Set oPres = ActivePresentation
  Set oSlides = oPres.Slides
  FileNum = FreeFile
  'Open output file
  ' NOTE:  errors here if file hasn't been saved
  Open oPres.Path & PathSep & "AllText.TXT" For Output As FileNum
  For Each oSld In oSlides    'Loop thru each slide
    For Each oShp In oSld.Shapes                'Loop thru each shape on slide
      'Check to see if shape has a text frame and text
      If oShp.HasTextFrame And oShp.TextFrame.HasText Then
        If oShp.Type = msoPlaceholder Then
            Select Case oShp.PlaceholderFormat.Type
                Case Is = ppPlaceholderTitle, ppPlaceholderCenterTitle
                    Print #iFile, "Title:" & vbTab & oShp.TextFrame.TextRange
                Case Is = ppPlaceholderBody
                    Print #iFile, "Body:" & vbTab & oShp.TextFrame.TextRange
                Case Is = ppPlaceholderSubtitle
                    Print #iFile, "SubTitle:" & vbTab & oShp.TextFrame.TextRange
                Case Else
                    Print #iFile, "Other Placeholder:" & vbTab & oShp.TextFrame.TextRange
            End Select
        Else
            Print #iFile, vbTab & oShp.TextFrame.TextRange
        End If  ' msoPlaceholder
      End If    ' Has text frame/Has text
    Next oShp
  Next oSld
  'Close output file
  Close #iFile
End Sub
  И здесь мы становимся немного хитрее и следуем за текстом, который есть в группах. И в группах внутри групп. Посмотрите на это слишком внимательно, и ваша голова может начать болеть.
Sub ExportText()
  Dim oPres As Presentation
  Dim oSlides As Slides
  Dim oSld As Slide         'Slide Object
  Dim oShp As Shape         'Shape Object
  Dim iFile As Integer      'File handle for output
  iFile = FreeFile          'Get a free file number
  Dim PathSep As String
  Dim FileNum As Integer
  Dim sTempString As String
  #If Mac Then
    PathSep = ":"
  #Else
    PathSep = "\"
  #End If
  Set oPres = ActivePresentation
  Set oSlides = oPres.Slides
  FileNum = FreeFile
  'Open output file
  ' NOTE:  errors here if file hasn't been saved
  Open oPres.Path & PathSep & "AllText.TXT" For Output As FileNum
  For Each oSld In oSlides    'Loop thru each slide
    ' Include the slide number (the number that will appear in slide's
    ' page number placeholder; you could also use SlideIndex
    ' for the ordinal number of the slide in the file
    Print #iFile, "Slide:" & vbTab & cstr(oSld.SlideNumber)
    For Each oShp In oSld.Shapes                'Loop thru each shape on slide
      'Check to see if shape has a text frame and text
      If oShp.HasTextFrame And oShp.TextFrame.HasText Then
        If oShp.Type = msoPlaceholder Then
            Select Case oShp.PlaceholderFormat.Type
                Case Is = ppPlaceholderTitle, ppPlaceholderCenterTitle
                    Print #iFile, "Title:" & vbTab & oShp.TextFrame.TextRange
                Case Is = ppPlaceholderBody
                    Print #iFile, "Body:" & vbTab & oShp.TextFrame.TextRange
                Case Is = ppPlaceholderSubtitle
                    Print #iFile, "SubTitle:" & vbTab & oShp.TextFrame.TextRange
                Case Else
                    Print #iFile, "Other Placeholder:" & vbTab & oShp.TextFrame.TextRange
            End Select
        Else
            Print #iFile, vbTab & oShp.TextFrame.TextRange
        End If  ' msoPlaceholder
      Else  ' it doesn't have a textframe - it might be a group that contains text so:
        If oShp.Type = msoGroup Then
            sTempString = TextFromGroupShape(oShp)
            If Len(sTempString) > 0 Then
                Print #iFile, sTempString
            End If
        End If
      End If    ' Has text frame/Has text
    Next oShp
  Next oSld
  'Close output file
  Close #iFile
End Sub
Function TextFromGroupShape(oSh As Shape) As String
' Returns the text from the shapes in a group
' and recursively, text within shapes within groups within groups etc.
    Dim oGpSh As Shape
    Dim sTempText As String
    If oSh.Type = msoGroup Then
        For Each oGpSh In oSh.GroupItems
            With oGpSh
                If .Type = msoGroup Then
                    sTempText = sTempText & TextFromGroupShape(oGpSh)
                Else
                    If .HasTextFrame Then
                        If .TextFrame.HasText Then
                            sTempText = sTempText & "(Gp:) " & .TextFrame.TextRange.Text & vbCrLf
                        End If
                    End If
                End If
            End With
        Next
    End If
    TextFromGroupShape = sTempText
NormalExit:
    Exit Function
Errorhandler:
    Resume Next
End Function